I could ask the opposite: why do people choose terminal vim when you can easily add nvim integration to editors like VSCode and get 98-100% of what vim gives you along with much easier configuration of all those extras you mention like autocomplete, hover reference, refactor, etc.?
That's a bit of an overstatement, because I really do love vim/nvim and nvim integration isn't that good, but the fact is that adding a feature in nvim still means researching and configuring it where in something like VSCode you open a new filetype, it asks "do you want support for this file", click yes and you're ready to go. I can spend a few days trying to get vim to work in the way I want it for a specific filetype/framework, or I can get 90% of what I want from VSCode in 30 seconds and still have vim navigation and command support.
That's a bit of an overstatement, because I really do love vim/nvim and nvim integration isn't that good, but the fact is that adding a feature in nvim still means researching and configuring it where in something like VSCode you open a new filetype, it asks "do you want support for this file", click yes and you're ready to go. I can spend a few days trying to get vim to work in the way I want it for a specific filetype/framework, or I can get 90% of what I want from VSCode in 30 seconds and still have vim navigation and command support.